Fluorinated compounds show high lubricity, water/oil repellency, etc. and are thus useful for surface treatment agents. When water/oil repellency is imparted to the surface of a substrate by such surface treatment agents, it becomes easier to wipe off dirt on the surface of the substrate, whereby removability of stains will be improved. Among fluorinated compounds, a fluorinated ether compound having a poly(oxy perfluoroalkylene) chain, wherein an ether bond (—O—) is present in the perfluoroalkylene chain, is a compound excellent in flexibility, which is particularly excellent in removability of stains of e.g. fats and oils.
It is known to use a composition containing a fluorinated ether compound which has a poly(oxyperfluoroalkylene) chain and has a hydrolyzable silyl group at its terminal, as a surface treatment agent such as an antifouling agent, a lubricant or a water/oil repellent (see Patent Documents 1 and 2.).